MethodHeat oil and butter in a thick-bottomed pan, add onions and sauté on medium heat for two to three minutes till light pink. Add tomatoes Capsicum and salt and continue to sauté on low heat till tomatoes are done. Add turmeric,red chilli, coriander powder and pav bhaji masala and continue to cook on low heat for 5-7 min.Add potato and 1/2 cup water if mixture is too dry and stir it and mash this Masala slightly.Add fresh coriander and stir to mix well. To serve, slit pav and Roast on tawa with little butter .Then arrange tomato and spread the onion-tomato masala (2 or 3 tbsp)and arrange cucumber and serve hotIf You want can use Sev or Mixture also.